Gel Patch

ABSTRACT

The present invention provides a gel patch comprising a base fabric, an adhesive layer, and a release liner in this order, wherein the adhesive layer contains a physiologically active substance, a water-soluble (meth)acrylic polymer, water, a surfactant, and poly(methyl acrylate/2-ethylhexyl acrylate), and the surfactant comprises a polyethylene glycol fatty acid ester or a polyoxyethylene sorbitan fatty acid ester.

TECHNICAL FIELD

The present invention relates to a gel patch.

BACKGROUND ART

Gel patches are a type of a poultice which is provided with an adhesive layer containing drugs formed onto a base fabric, and the adhesive layer is usually coated with a release liner. Because gel patches generally include much moisture and have a thick adhesive layer, the penetration of active components through the skin is promoted and irritation to the skin is reduced. However, because the moisture in the adhesive layer is evaporated over time, the adhesion of the gel patch may decrease with time.

CITATION LIST Patent Literature

[Patent Literature 1] JP 2003-93434 A

SUMMARY OF INVENTION Technical Problem

According to findings of the inventors of the present invention, if poly(methyl acrylate/2-ethylhexyl acrylate) is contained in an adhesive layer of a gel patch, decrease of adhesion can be suppressed, but the peeling strength (peeling force of the liner) at the time of peeling of the release liner from the adhesive layer may also become high.

In order to solve the above-described problem, an object of the present invention is to provide a gel patch with an adhesive layer containing poly(methyl acrylate/2-ethylhexyl acrylate) capable of peeling a release liner with less force.

Solution to Problem

The present invention is a gel patch comprising a base fabric, an adhesive layer, and a release liner in this order, wherein the adhesive layer comprises a physiologically active substance, a water-soluble (meth)acrylic polymer, water, a surfactant, and poly(methyl acrylate/2-ethylhexyl acrylate), and the surfactant includes a polyethylene glycol fatty acid ester or a polyoxyethylene sorbitan fatty acid ester.

Because the gel patch of the present invention comprises poly(methyl acrylate/2-ethylhexyl acrylate) in the adhesive layer, decrease of adhesion of the gel patch after a long time has elapsed can be suppressed. In addition, the specific surfactant coexists with other components in the adhesive layer, and thus it is possible to maintain a low liner peeling force.

The poly(methyl acrylate/2-ethylhexyl acrylate) may be derived from a poly(methyl acrylate/2-ethylhexyl acrylate) emulsion, and the surfactant preferably include a monofatty acid ester of polyethylene glycol (hereinafter may also be referred to as “PEG”) or a monofatty acid ester of polyoxyethylene sorbitan. More preferably, the fatty acid constituting the monofatty acid ester is a fatty acid having 12 to 18 carbon atoms. Specifically, the fatty acid having 12 to 18 carbon atoms preferably include stearic acid or oleic acid.

Advantageous Effects of Invention

According to the gel patch of the present invention, the release liner can be peeled with less force.

DESCRIPTION OF EMBODIMENTS

The present invention will be described below with reference to an embodiment.

As used herein, the term “liner peel force” means the peeling strength for peeling a release liner from an adhesive layer of a gel patch (i.e., the load required for peeling).

The liner peel force is preferably 0.11 N/25 mm or less, more preferably 0.10 N/25 mm or less, considering the usefulness of the gel patch. When the liner peel force is 0.11 N/25 mm or less, the user thereof may find no difficulty in peeling the release liner.

An embodiment of the present invention is a gel patch provided with an adhesive layer formed on a base fabric, which further comprises a release liner arranged on a back side of a surface contacting the base fabric of the adhesive layer, and the adhesive layer contains a physiologically active substance, a water-soluble (meth)acrylic polymer, water, a surfactant, and poly(methyl acrylate/2-ethylhexyl acrylate), and the surfactant comprises a polyethylene glycol fatty acid ester or a polyoxyethylene sorbitan fatty acid ester. More specifically, in the gel patch of the present embodiment, the base fabric, the adhesive layer, and the release liner are laminated together in this order.

Examples of the base fabric include woven fabric, nonwoven fabric, a resin film, a foamed sheet, and paper, and examples of the woven fabric includes knitted fabric. When woven fabric, nonwoven fabric, or a resin film is used as the base fabric, examples of a material thereof include, polyolefins such as polyethylene, polypropylene, and polybutylene; polyesters such as polyethylene terephthalate; rayon; polyurethane; and cotton, and one of these materials can be used alone or two or more of them can be used in combination. The base fabric may include a single layer structure or may include a multilayer structure. For the material of the base fabric, polyester is more preferable.

For the base fabric, nonwoven fabric or woven fabric are preferable, and nonwoven fabric or woven fabric having a predetermined elongation recovery rate is particularly preferable. The term “elongation recovery rate” herein refers to a value measured in compliance with “JIS L 1096 Testing Methods for Woven and Knitted Fabrics”. It is preferable to use the nonwoven fabric or woven fabric having the elongation recovery rate because the base fabric expands in accordance with the motion of the portion in which the gel patch is applied onto movable portions such as a joint.

When the base fabric is nonwoven fabric, for example, the load applied when expanded by 50% is preferably 1 to 5 N/2.5 cm in the longitudinal direction (in the long axis direction) and 0.1 to 3 N/2.5 cm in the horizontal direction (in the short axis direction). The recovery rate at expansion by 50% is preferably 60 to 99%, for example, preferably 65 to 95%, and more preferably 70 to 90%. A suitable surface density is 80 to 120 g/m², preferably 90 to 110 g/m², for example. A suitable thickness of the base fabric is 0.5 to 2 mm, for example. The bending resistance of the base fabric (the measuring method for the bending resistance is the 45° cantilever method provided in JIS L 1096) can be 20 to 40 mm in the longitudinal direction (in the long axis direction) and 10 to 35 mm in the horizontal direction (in the short axis direction), and is preferably 25 to 35 mm in the longitudinal direction (in the long axis direction) and 15 to 30 mm in the horizontal direction (in the short axis direction).

When woven fabric, in particular, knitted fabric, is used as the base fabric, for example, the knitted fabric includes knitted fabric obtained by working the material into the form of a cloth by aggregating the stitches by circular knitting, warp knitting, weft knitting, or the like, for example. Preferable examples of the knitted fabric include a knitted fabric obtained by using one alone or two or more in combination of materials such as polyester-based material, nylon-based material, polypropylene-based material, rayon-based material, and a knitted fabric including polyester-based polyethylene terephthalate which has a little interaction with a drug is particularly preferable.

In particular, when the base fabric is woven fabric, the load applied when expanded by 50% is preferably 1 to 5 N/2.5 cm in the longitudinal direction (in the long axis direction) and 0.1 to 3 N/2.5 cm in the horizontal direction (in the short axis direction), for example. The recovery rate at expansion by 50% is preferably 60 to 99%, for example, preferably 65 to 95%, and more preferably 70 to 90%. The bending resistance of the base fabric can be 10 to 30 mm in the longitudinal direction (in the long axis direction) and 10 to 30 mm in the horizontal direction (in the short axis direction), and is preferably 15 to 25 mm in the longitudinal direction (in the long axis direction) and 15 to 25 mm in the horizontal direction (in the short axis direction).

When a paste containing water is spread on a woven fabric, there is a threat of water seeping through the mesh of the woven fabric, however, if the surface density of the fabric made of polyethylene terephthalate is within 80 to 150 g/m², the paste tends to be securely spread without the water contained in the paste seeping through the mesh of the woven fabric, and also, thereby the anchoring property between the woven fabric and the paste can be maintained.

Preferably, the polyethylene terephthalate woven fabric has a modulus in the longitudinal direction (in the long axis direction) of 2 to 12 N/5 cm and a modulus in the horizontal direction (in the short axis direction) of 2 to 8 N/5 cm (the modulus as measured according to JIS L 1018:1999). When the modulus is lower than 2 N/5 cm (in the longitudinal direction) or 2 N/5 cm (in the horizontal direction), when the paste is applied, the woven fabric extends, and thus the adhesive may seep through the mesh and thereby the function as the gel patch may decrease. When the modulus is higher than 12 N/5 cm (in the longitudinal direction) or 8 N/5 cm (in the horizontal direction), the expansion property may become poor, and thus it may become difficult for the resulting gel patch to follow the expansion of the skin when the gel patch is applied to a bending portion.

The adhesive layer contains a physiologically active substance, a water-soluble (meth)acrylic polymer, water, a surfactant, and poly(methyl acrylate/2-ethylhexyl acrylate), and the above-described surfactant comprises a polyethylene glycol fatty acid ester or a polyoxyethylene sorbitan fatty acid ester.

The physiologically active substance may be a substance having a percutaneous absorption characteristic that exhibits its pharmacological activity when administered into a subject's body. The physiologically active substance may be a water-soluble substance or a fat-soluble substance. Because the adhesive layer of a gel patch contains a large quantity of water, the physiologically active substance is preferably a water-soluble substance. When the physiologically active substance is a fat-soluble substance, the physiologically active substance may be a substance that has an action of a surfactant. Examples of the physiologically active substance include non-steroid anti-inflammatory agents, or esters thereof, such as felbinac, flurbiprofen, diclofenac, diclofenac sodium, methyl salicylate, glycol salicylate, indomethacin, ketoprofen, and ibuprofen; anti-histamine agents such as diphenhydramine and chlorpheniramine; pain killers such as aspirin, acetaminophen, ibuprofen, and loxoprofen sodium; local anesthetics such as lidocaine and dibucaine; muscle relaxants such as suxamethonium chloride; anti-fungal agents such as clotrimazole; anti-hypertensive agents such as clonidine; vasodilators such as nitroglycerine and isosorbide dinitrate; vitamin preparations such as vitamin A, vitamin E (tocopherol), tocopherol acetate, vitamin K, octotiamine, and riboflavin butyrate; prostaglandins; scopolamine; fentanyl; chile pepper extracts; and nonylic acid amides. For the physiologically active substance, one type thereof may be used alone or two or more types of them can be used in combination.

In addition, the adhesive layer may contain fruit-derived components such as rose fruit extract, orange extract, orange fruit juice, raspberry extract, kiwi extract, cucumber extract, gardenia extract, grapefruit extract, hawthorn extract, Japanese pepper extract, quickthorn extract, juniper extract, jujubi extract, Lansium Domesticum extract, tomato extract, grape extract, luffa extract, lime juice, apple extract, apple fruit juice, lemon extract, and lemon fruit juice; water-soluble placenta extract; allantoin; lecithin; amino acids; kojic acid; proteins; saccharides; hormones; placental extracts; ingredients extracted from various types of herbal medicines such as aloe and licorice; and extracts and substances such as Angelica keiskei extract, avocado extract, sweet hydrangea leaf extract, marsh mallow extract, arnica extract, Ginkgo extract, aqua anisi extract, Curcuma extract, oolong tea extract, Scutellaria baicalensis extract, phellodendron bark extract, barley extract, Dutch mustard extract, seaweed extract, hydrolyzed elastin, hydrolyzed wheat powder, hydrolyzed silk, camomile extract, Artemisia capillaris flower extract, licorice extract, Sabdariffa extract, guanosine, Kumazasa (Sasa albo-marginata) extract, walnut extract, clematis extract, yeast extract, burdock extract, comfrey extract, bilberry extract, red thorowax root extract, abdominal stalk extract, sage extract, Saponaria officinalis extract, Sasa bamboo extract, Crataegus cuneata fruit extract, shiitake mushroom extract, rehmannia root extract, Shikon extract, linden extract, Shimotsukeso (Filipendula multijuga) extract, sweet flag root extract, birch extract, Equisetum arvense extract, Lonicera japonica Thunberg extract, Hedera helix extract, Crataegus oxyacantha extract, Sambucus nigra extract, Achillea millefolium extract, peppermint extract, mallow extract, Swertia japonica extract, jujubi extract, thyme extract, clove extract, Imperata cylindrica extract, Citrus unshiu peel extract, Aurantii Amari Cortex extract, Houttuynia cordata extract, Natto (fermented soy beans) extract, carrot extract, Rosa multiflora extract, hibiscus extract, ophiopogon tuber extract, parsley extract, honey, Parietaria officinalis extract, Isodon japonicus extract, bisabolol, Tussilago farfara extract, Petasites japonica Miq. extract, hoelen extract, butcher's bloom extract, propolis, peppermint extract, linden extract, hop extract, pine extract, horse chestnut extract, Lysichitum camtschatcense extract, Sapindus mukurossi extract, peach leaf extract, Centaurea cyanus extract, eucalyptus extract, citron extract, mugwort extract, lavender extract, lettuce extract, Astragalus sinicus extract, rose extract, rosemary extract, Roman chamomile extract, and royal jelly extract.

The water-soluble (meth)acrylic polymer is a polymer obtained by polymerizing a (meth)acryloyl group-containing compound having a functional group that exhibits water-solubility (hydrophilic group), and exhibits an adhesive property when the water-soluble (meth)acrylic polymer is contained together with water in the adhesive layer. The water-soluble (meth)acrylic polymer is, for example, a polymer obtained by polymerizing a polyacrylic acid or a neutralized product thereof, or a compound having a (meth)acryloyl group such as (meth)acrylic acid ester having a hydrophilic group and (meth)acrylic acid amide having a hydrophilic group. In addition, the water-soluble (meth)acrylic polymers may be a homopolymer obtained from a compound having a (meth)acryloyl group of one type or a copolymer obtained from a compound having (meth)acryloyl groups of two types or more.

The hydrophilic group may be any of a cationic hydrophilic group, an anionic hydrophilic group, and a nonionic hydrophilic group. Examples of the cationic hydrophilic group include quaternary ammonium, and examples of the anionic hydrophilic group include a carboxy group, a sulfonic group, and a phosphate group, and examples of the nonionic hydrophilic group include a hydroxy group and an amino group. The term “(meth)acryloyl group” means an acryloyl group or a methacryloyl group, and the term “(meth)acrylic acid” is defined in the similar manner.

Preferably, the water-soluble (meth)acrylic polymer include polyacrylic acid. The content of the polyacrylic acid in the adhesive layer is preferably 1 to 5% by mass, more preferably 2 to 6% by mass, in relation to the mass of the entire adhesive layer as the reference. By adjusting the content of the polyacrylic acid to 1% by mass or more, the formability and the shape retention of the adhesive layer tend to more greatly improve, and by adjusting the content of the polyacrylic acid to 5% by mass or less, the rigidity of the adhesive layer tends not to become high and the adhesion to the skin tends to become higher.

The water-soluble (meth)acrylic polymer may preferably include a neutralized polyacrylate. The neutralized polyacrylate may be a completely neutralized product of polyacrylic acid, a partially neutralized product of polyacrylic acid, or a mixture thereof. The term “neutralized polyacrylate” refers to a salt of a polyacrylic acid, and a sodium salt, a potassium salt, a calcium salt, or an ammonium salt thereof, for example, can be used.

For the neutralized polyacrylate, the partially neutralized polyacrylate is preferable because of its high initial adhesion and temporal adhesion. In the neutralized polyacrylate, in one polymer chain, a structural unit derived from acrylic acid and a structural unit derived from acrylic acid salt are present at an arbitrary ratio. For the partially neutralized polyacrylate, it is preferable to use a carboxy group in one polymer chain of which 20 to 80 mol % has been neutralized.

The content of the neutralized polyacrylate in the adhesive layer is preferably 1 to 6% by mass, more preferably 2 to 6% by mass, in relation to the mass of the entire adhesive layer as the reference. By adjusting the content of the neutralized polyacrylate to 1% by mass or more, an excellent adhesion of the neutralized polyacrylate can be obtained, and by adjusting the content of the neutralized polyacrylate to 6% by mass or less, the formability and the shape retention of the adhesive layer improve. Polyacrylic acid and the neutralized polyacrylate (preferably the partially neutralized polyacrylate) may be used in combination, and a suitable content of the respective substance and product when they are used in combination is as described above.

In the (meth)acrylic acid ester having a hydrophilic group, the portion of (meth)acrylic acid ester is preferably an alkyl (meth)acrylic acid ester. The alkyl portion is preferably C1-10 alkyl, and more preferably C1-8 alkyl. In the (meth)acrylic acid ester having a hydrophilic group, the hydrophilic group is preferably present in the alkyl portion.

The adhesive layer contains poly(methyl acrylate/2-ethylhexyl acrylate). If the adhesive layer of a conventional gel patch has a light weight, the water content may easily decrease and the adhesion may thus easily decrease. On the other hand, in the present embodiment, when the adhesive layer contains poly(methyl acrylate/2-ethylhexyl acrylate), an excellent adhesion tends to be easily maintained after a long period of time has elapsed even if the mass of the adhesive layer is relatively small.

The poly(methyl acrylate/2-ethylhexyl acrylate) is preferably an aqueous emulsion containing water as a medium. Also, the emulsion of poly(methyl acrylate/2-ethylhexyl acrylate) is preferably an emulsion containing poly(oxyethylene) nonyl phenyl ether as a surfactant or a protective colloid. The residue on evaporation (nonvolatile content) by heating at a temperature higher than the boiling point of the medium (e.g., heating at 105° C. for 3 hours) is preferably 57 to 61%. Examples of such an emulsion include NIKASOL TS-620 (trade name, a product of NIPPON CARBIDE Industries Co., Inc.). According to the Japanese standards of medical package inserts (2013), when NIKASOL TS-620 is evaporated and dried in a water bath and the resultant is dried at 105° C. for 3 hours, the amount of the residue on evaporation is 57 to 61%.

The gel patch of the present embodiment contains water in the adhesive layer. Because the adhesive layer contains water, the skin permeability of the drug improves and its pharmacological action is more effectively exhibited.

The water content is preferably 10 to 90% by mass, more preferably 15 to 88% by mass, and yet more preferably 18 to 85% by mass in relation to the mass of the adhesive layer as the reference.

The surfactant comprises a polyethylene glycol fatty acid ester or a polyoxyethylene sorbitan fatty acid ester. If the physiologically active substance is a fat-soluble substance, by combination of a polyethylene glycol fatty acid ester or a polyoxyethylene sorbitan fatty acid ester therewith, a micelle or an emulsion can be easily formed, and the apparent solubility of the physiologically active substance to the adhesive layer is improved.

Examples of preferable surfactant include a monofatty acid ester of polyethylene glycol or a monofatty acid ester of polyoxyethylene sorbitan. The fatty acid constituting the monofatty acid ester described above is preferably a fatty acid having 12 to 18 carbon atoms. Examples of the fatty acid having 12 to 18 carbon atoms include lauric acid, myristic acid, pentadecylic acid, palmitic acid, palmitoleic acid, margaric acid, stearic acid, oleic acid, vaccenic acid, linoleic acid, and linolenic acid, and the fatty acid having 12 to 18 carbon atoms is preferably margaric acid, stearic acid, or oleic acid. A particularly preferable surfactant is monostearic acid polyethylene glycol or polyoxyethylene sorbitan monooleate.

The pH of the adhesive layer is preferably 4.7 to 5.1, and more preferably 4.9 to 5.1. By adjusting the pH to 4.7 or higher, the irritation to the skin decreases, and by adjusting the pH to 5.1 or lower, the formability and the shape retention of the gel patch can be improved. Particularly, if the base fabric is woven fabric, in particular, if the base fabric is knitted fabric, water may seep from the adhesive layer during forming of the adhesive layer, but if the pH is 4.9 to 5.1, the seeping tends to be suppressed. Note that the pH can be measured by referring to the pH measurement method by the Japanese Pharmacopoeia general test method and by using a glass composite electrode and diluting a sample with purified water by 20 times, for example.

The mass of the adhesive layer may be 214 to 1000 g/m², 400 to 1000 g/m², or 400 to 650 g/m². By preferably adjusting the mass of the adhesive layer to the range of 400 to 650 g/m², an excellent feel of fitness can be obtained and the adhesion for a longer time period can be obtained. If the mass of the adhesive layer is adjusted within the above-described range, the thickness of the entire gel patch can be reduced to be thin, thus the gel patch may easily follow the skin, and further, because the step from the peripheral portions may be small when attached, the gel patch tends not to be easily peeled.

To the adhesive layer, other components may be further added, such as a solubilizing agent, a crosslinking agent, a moisturizing agent, a refreshing agent, a stabilizer, an inorganic powder, a coloring agent, a flavoring agent, and a pH adjustor.

The solubilizing agent is added so that the components contained in the adhesive layer would not be precipitated. Examples of the solubilizing agent include crotamiton; N-methylpyrrolidone; polyalkylene glycols such as polyethylene glycol (PEG) and polybutylene glycol; polyvinyl alcohols; and fatty acid esters such as isopropyl myristate and diethyl adipate. For the solubilizing agents, one of them can be used alone or two or more of them can be used in combination. The content of the solubilizing agent is preferably 0.1 to 10% by mass in relation to the mass of the adhesive layer as the reference.

The crosslinking agent is added to adjust the crosslinking reaction of the water-soluble (meth)acrylic polymer, and the followingness of the gel patch to the skin can be adjusted by adjusting the content of the crosslinking agent. For the crosslinking agent, agents that are generally used as a gel patch can be used.

The moisturizing agent is not particularly limited and an agent capable of suppressing evaporation of moisture from the adhesive layer over time can be used. Examples of the moisturizing agent include gelatines and polyhydric alcohols such as sorbitol, glycerine, ethyleneglycol, propylene glycol, butanediol, and liquid paraffin. For the moisturizing agents, one of them may be used alone or two or more of them may be used in combination. The content of the moisturizing agent is preferably 3 to 70% by mass in relation to the mass of the adhesive layer as the reference.

The refreshing agent brings about cool and refreshing feeling to the user when the gel patch is used, and the refreshing agent may include aroma. Examples of the refreshing agent include thymol, 1-menthol, dl-menthol, 1-isopulegol, and a peppermint oil, and it is preferable to use 1-menthol. The content of the refreshing agent is preferably 0.5 to 3% by mass in relation to the mass of the adhesive layer as the reference.

The stabilizing agent improves the conservation stability of physiologically active substances against light (ultraviolet (UV) light, in particular), heat, or oxygen. Examples of the stabilizing agent include oxybenzone, dibutyl hydroxytoluene (BHT), sodium edetate, UV absorbing agent (e.g., a dibenzoyl methane derivative). The content of the stabilizing agent is preferably 0.01 to 1% by mass in relation to the mass of the adhesive layer as the reference.

The inorganic powder is added to adjust the stickiness obtained when the gel patch is used. Examples of the inorganic powder include alumina, light silica, titanium oxide, and synthetic aluminum silicate. The content of the inorganic powder is preferably 0.1 to 10% by mass in relation to the mass of the adhesive layer as the reference.

The gel patch of the present embodiment further comprises a release liner on a surface opposite to the surface of the adhesive layer contacting the base fabric.

The release liner is laminated on the surface opposite to the base fabric from the adhesive layer. Because the release liner is provided, decrease of the water content in the adhesive layer during storage can be prevented and adhesion of dusts to the adhesive layer can be suppressed.

The material of the release liner is not particularly limited and a liner generally used by persons skilled in the art can be used. Examples of the material of the release liner include polyethylene, polypropylene, polyethylene terephthalate, and paper, and one of them may be used alone or two or more of them may be used in combination. The material of the release liner is preferably polypropylene or polyethylene terephthalate.

The gel patch may be stored in an inside of a pouch. By storing the gel patch inside a pouch, decrease of the water content in the adhesive layer during storage can be prevented and adhesion of dusts to the adhesive layer can be suppressed.

The gel patch of the present embodiment can be produced as follows. First, the physiologically active substance, the water-soluble (meth)acrylic polymer, water, the surfactant, and poly(methyl acrylate/2-ethylhexyl acrylate) are mixed together sufficiently to prepare a paste. The obtained paste is uniformly spread on the release liner, and the base fabric is laminated thereon to obtain the gel patch. Note that the gel patch may also be produced by spreading the paste onto the base fabric and then laminating the release liner thereon.

Also, the present invention provides a method for producing a gel patch comprising a base fabric, an adhesive layer, and release liner in this order, the production method comprising forming an adhesive layer from an adhesive paste obtained by mixing a physiologically active substance, a water-soluble (meth)acrylic polymer, water, a surfactant and poly(methyl acrylate/2-ethylhexyl acrylate), wherein the surfactant comprises a fatty acid ester of polyethylene glycol or a fatty acid ester of polyoxyethylene sorbitan.

It is preferable that the poly(methyl acrylate/2-ethylhexyl acrylate) be derived from a poly(methyl acrylate/2-ethylhexyl acrylate) emulsion. It is preferable that the water-soluble (meth)acrylic polymer contain a polyacrylic acid or a neutralized polyacrylate. It is preferable that the fatty acid ester of polyethylene glycol contain a monofatty acid ester of polyethylene glycol. It is preferable that the fatty acid ester of polyoxyethylene sorbitan contain a monofatty acid ester of polyoxyethylene sorbitan. It is preferable that the fatty acid constituting the fatty acid monoester comprises a fatty acid having 12 to 18, and it is more preferable that the fatty acid comprises stearic acid or oleic acid.

The present invention also provides a method for suppressing an increase in a liner peeling force with time of a gel patch comprising a base fabric, a plaster layer and a release liner in this order, the suppression method comprising a step of forming an adhesive layer from a paste obtained by mixing a physiologically active substance, a water-soluble (meth)acrylic polymer, water, a surfactant and poly(methyl acrylate/2-ethylhexyl acrylate), wherein the surfactant comprises a fatty acid ester of polyethylene glycol or a fatty acid ester of polyoxyethylene sorbitan.

It is preferable that the poly(methyl acrylate/2-ethylhexyl acrylate) be derived from a poly(methyl acrylate/2-ethylhexyl acrylate) emulsion. It is preferable that the water-soluble (meth)acrylic polymer contain a polyacrylic acid or a neutralized polyacrylate. It is preferable that the fatty acid ester of polyethylene glycol contain a monofatty acid ester of polyethylene glycol. It is preferable that the fatty acid ester of polyoxyethylene sorbitan contain a monofatty acid ester of polyoxyethylene sorbitan. It is preferable that the fatty acid constituting the fatty acid monoester comprise a fatty acid having 12 to 18 carbon atoms, and it is more preferable that the fatty acid comprise stearic acid or oleic acid.

EXAMPLE

(Preparation of the Gel Patch)

As shown in Table 1, the components were sufficiently mixed together to prepare a paste. The obtained paste was uniformly spread onto the release liner, a base fabric was laminated thereon, and the release liner was peeled off to obtain the gel patches of Examples 1, 2 and Comparative Examples 1 to 3. Note that for the poly(methyl acrylate/2-ethylhexyl acrylate), NIKASOL TS-620 (trade name, a product of NIPPON CARBIDE Industries Co., Inc.) was used.

TABLE 1 Example 1 Example 2 l-Menthol 1 1 Glycol salicylate 2 2 Tocopherol acetate 1 1 Gelatin 2.5 2.5 Partially neutralized 3 3 Polyacrylate Polyacrylic acid 3.5 3.5 Polyvinyl alcohol 2.5 2.5 NIKASOL TS-620 8.35 8.35 PEG monostearate 0.5 0 POE hydrogenated 0 0 castor oil Polysorbate 80 0 0.5 Crosslinker 0.55 0.55 D-sorbitol 7 7 Glycerin 23 23 Other ingredients 1.02 1.02 Purified water 44.08 44.08 Total 100 100 Comparative Comparative Comparative Example 1 Example 2 Example 3 l-Menthol 1 1 1 Glycol salicylate 2 2 2 Tocopherol acetate 1 1 1 Gelatin 2.5 2.5 2.5 Partially neutralized 3 3 3 Polyacrylate Polyacrylic acid 3.5 3.5 3.5 Polyvinyl alcohol 2.5 2.5 2.5 NIKASOL TS-620 0 8.35 8.35 PEG monostearate 0 0 0 POE hydrogenated 0 0 0.5 castor oil Polysorbate 80 0 0 0 Crosslinker 0.55 0.55 0.55 D-sorbitol 7 7 7 Glycerin 23 23 23 Other ingredients 1.02 1.02 1.02 Purified water 52.93 44.58 44.08 Total 100 100 100

(Evaluation)

The obtained gel patch was cut so that the width thereof was 2.5 cm, and the load required for peeling when the gel patch was peeled off at a constant speed of 300 mm/min by using a Tensilon type tensile testing machine (trade name: RTA-100, a product of A&D Company, Limited).

The results are shown in Table 2. In the gel patch of the Comparative Example 3 containing poly(methyl acrylate/2-ethylhexyl acrylate) in the adhesive layer, the liner peeling force increased in comparison with the gel patch of the Comparative Example 1. On the other hand, in the gel patches of Examples 1 and 2, in which the adhesive layer further contains monostearic acid polyethylene glycol (PEG), or polysorbate 80 in addition to poly(methyl acrylate/2-ethylhexyl acrylate), the liner peeling force was the same as that of the gel patch of the Comparative Example 1.

TABLE 2 Example 1 Example 2 Liner peeling 0.072 0.085 force (N/25 mm) Comparative Comparative Comparative Example 1 Example 2 Example 3 Liner peeling 0.08 0.112 0.13 force (N/25 mm)

Instead of salicylic acid glycol and tocopherol acetate in Example 1, felbinac, ketoprofen, and diclofenac sodium were combined so that the mass thereof was 3% in relation to the mass of the entire adhesive layer to obtain the gel patches of Examples 3 to 5.

The liner peeling force was measured for the gel patches of Examples 3 to 5, and results similar to those of Example 1 were obtained.

(Preparation of the Gel Patch)

In accordance with the composition described in Table 3, the components were sufficiently mixed to prepare a paste. The resulting paste was uniformly spread over a release liner, and a base fabric was laminated thereon, followed by the peeling of the release liner to obtain each of the gel patches of Example 6 and Comparative Example 4. Note that NIKASOL TS-620 (trade name, manufactured by NIPPON CARBIDE INDUSTRIES CO., INC.) was used as poly(methyl acrylate/poly2-ethylhexyl acrylate).

TABLE 3 Comparative Example 6 Example 4 l-Menthol 0.3 0.3 Gelatin 2.5 2.5 Partially neutralized Polyacrylate 4 4 Polyvinyl alcohol 2.5 2.5 NIKASOL TS-620 17 0 PEG monostearate 0.5 0.5 Crosslinker 1 1 Glycerin 33 30 Other ingredients 6.2 4.2 Purified water 33 55 Total 100 100

(Evaluation): The gel patches of Example 6 and Comparative Example 4 were affixed to the skins of 10 test subjects, and the temperature of the affixed skin was measured with time. The results are shown in Table 4. Note that the temperatures described in Table 4 are the average values of the test subjects. With comparison of the lowest values of the skin temperatures before being affixed and the lowest values of the skin temperatures after being affixed, the difference was calculated as “body temperature reduction”. The values obtained by dividing the values of “body temperature reduction” by the moisture contents of the gel patches were recorded as “body temperature reduction per unit moisture”.

The gel patch of Example 6 had the effect of “body temperature reduction per unit moisture” of about 1.3 times higher than that of the gel patch of Comparative Example 4, and efficiently reduced the skin temperatures of the test subject.

TABLE 4 Comparative Example 6 Example 4 Temperature [° C.] 34.78 34.8 (before being affixed) Temperature [° C.] 31.49 30.57 (the lowest value after being affixed) Body temperature reduction 3.29 4.23 [° C.] Body temperature reduction 0.0997 0.0769 per unit moisture 1.296 1 

1. A gel patch comprising a base fabric, an adhesive layer, and a release liner in this order, wherein the adhesive layer comprises a physiologically active substance, a water-soluble (meth)acrylic polymer, water, a surfactant, and poly(methyl acrylate/2-ethylhexyl acrylate), and the surfactant comprises a polyethylene glycol fatty acid ester or a polyoxyethylene sorbitan fatty acid ester.
 2. The gel patch according to claim 1, wherein the poly(methyl acrylate/2-ethylhexyl acrylate) is derived from a poly(methyl acrylate/2-ethylhexyl acrylate) emulsion.
 3. The gel patch according to claim 1, wherein the water-soluble (meth)acrylic polymer comprises polyacrylic acid or a neutralized polyacrylate.
 4. The gel patch according to claim 1, wherein the polyethylene glycol fatty acid ester comprises a monofatty acid ester of polyethylene glycol, and the polyoxyethylene sorbitan fatty acid ester comprises a monofatty acid ester of polyoxyethylene sorbitan.
 5. The gel patch according to claim 4, wherein a fatty acid constituting the monofatty acid ester is a fatty acid having 12 to 18 carbon atoms.
 6. The gel patch according to claim 5, wherein the fatty acid having 12 to 18 carbon atoms comprises stearic acid or oleic acid.
 7. The gel patch according to claim 2, wherein the water-soluble (meth)acrylic polymer comprises polyacrylic acid or a neutralized polyacrylate.
 8. The gel patch according to claim 2, wherein the polyethylene glycol fatty acid ester comprises a monofatty acid ester of polyethylene glycol, and the polyoxyethylene sorbitan fatty acid ester comprises a monofatty acid ester of polyoxyethylene sorbitan.
 9. The gel patch according to claim 3, wherein the polyethylene glycol fatty acid ester comprises a monofatty acid ester of polyethylene glycol, and the polyoxyethylene sorbitan fatty acid ester comprises a monofatty acid ester of polyoxyethylene sorbitan.
 10. The gel patch according to claim 7, wherein the polyethylene glycol fatty acid ester comprises a monofatty acid ester of polyethylene glycol, and the polyoxyethylene sorbitan fatty acid ester comprises a monofatty acid ester of polyoxyethylene sorbitan.
 11. The gel patch according to claim 8, wherein a fatty acid constituting the monofatty acid ester is a fatty acid having 12 to 18 carbon atoms.
 12. The gel patch according to claim 9, wherein a fatty acid constituting the monofatty acid ester is a fatty acid having 12 to 18 carbon atoms.
 13. The gel patch according to claim 10, wherein a fatty acid constituting the monofatty acid ester is a fatty acid having 12 to 18 carbon atoms.
 14. The gel patch according to claim 11, wherein the fatty acid having 12 to 18 carbon atoms comprises stearic acid or oleic acid.
 15. The gel patch according to claim 12, wherein the fatty acid having 12 to 18 carbon atoms comprises stearic acid or oleic acid.
 16. The gel patch according to claim 13, wherein the fatty acid having 12 to 18 carbon atoms comprises stearic acid or oleic acid. 